Lesion of serotonergic neurons antagonizes clonidine induced suppression of avoidance behavior and locomotor activity in rats.
The effects of clonidine on avoidance acquisition and locomotor activity were studied in male Wistar rats with 5,6-dihydroxytryptamine (5,6-DHT) lesions of the median raphe nucleus. Lesioned animals showed marked depletion in forebrain serotonin and 5-hydroxyindole acetic acid concentrations. clonidine (0.2 mg/kg IP in a single daily dose for 6 consecutive days) inhibited avoidance acquisition and reduced locomotor activity in unlesioned rats. In 5,6-DHT rats clonidine failed to produce depressive effect. The resistance of raphe-lesioned rats to clonidine is discussed on the basis of possible interaction between noradrenergic and serotonergic brain systems.
D015115:5,6-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D003000:Clonidine / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D009474:Neurons / Q000502:physiology*; D051381:Rats; D012701:Serotonin / Q000502:physiology*
D012701:Serotonin; D003000:Clonidine; D015115:5,6-Dihydroxytryptamine